Morphometric Analysis of Middle Omo Gibe Watershed for Land Degradation Assessment Using GIS Techniques, Southern Ethiopia

Now a day, the problem of land degradation is increasingly prevailing in many parts of the world, mostly with its strong effect on the economy and environment of the developing world and closely linked with the use of environmental resources, particularly land resources. Healthy and productive land resources like soil, water, and biodiversity, which are the foundation of societies and economies, have been seriously affected by global land degradation and study watershed in particular. The research has been undertaken in the Middle Omo River watershed, Southern Ethiopia, to assess the extent and status of land degradation using GIS-based morphometric analysis. The geospatial analysis of the watershed gives a detailed understanding of its geomorphological, climatic, relief, and drainage characteristics, which helps to identify the land degradation problems and their impacts on environmental resources. The analysis of different morphometric parameters such as stream order, stream number, stream length, Mean Stream Length Ratio, and bifurcation ratio is calculated and analyzed by SRTM Void Filled (3 arc-seconds resolution) Digital Elevation Model. Areal and relief aspects of morphometric parameters such as basin area, basin perimeter, texture ratio, basin relief, relief Ratio, absolute relief, relative relief, dissection index, and ruggedness index have been used and calculated by using high-resolution SRTM 1-ARC- Second Global digital elevation model (DEM). The results of the morphometric analysis show that the relief and drainage features of the watershed have paved the way for rapid soil loss and erosion, which give rise to land degradation in the watershed. On the other hand, the lithology, relief structure, and tectonics have determined the drainage patterns of the catchment. The initial field survey assessment of land degradation indicates that population growth, intensive land use/over-cultivation, overgrazing, deforestation, shortage of fallow period, expanded cultivation of steep slopes, lack of adoption of soil and water conservation measures, inadequate land cover during the erosive period are the modulation factors of land degradation in the studied watershed.